Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. One example routing protocol used for LLNs is a protocol called Routing Protocol for LLNs or “RPL,” which is a distance vector routing protocol that builds a Destination Oriented Directed Acyclic Graph (DODAG, or simply DAG) in addition to a set of features to bound the control traffic, support local (and slow) repair, etc. The RPL architecture provides a flexible method by which each node performs DODAG discovery, construction, and maintenance.
Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. For example, communication in LLNs can be affected by various communication conditions (e.g., temporal changes in interference, physical obstruction, propagation changes, etc.) that change over time. In addition, time scales of such temporal changes are variable and can range between milliseconds (e.g. transmissions from other transceivers) to months (e.g. seasonal changes of outdoor environment). Accordingly, nodes within the LLN can be potentially unreachable due to the various communication conditions. In particular, detecting these potentially unreachable nodes and re-routing messages destined for the unreachable nodes remains problematic for LLN networks.